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World Sleep Day

13 March 2020
Researchers examining the impact of sleep on health
In honour of World Sleep Day on Friday 13 March, we caught up with two Faculty of Medicine and Health researchers who are challenging conventional wisdom in the field of sleep.
Dr Kristina Cook, Research Fellow, Northern Clinical School

Dr Kristina Cook, research fellow, Northern Clinical School

Dr Kristina Cook

I work in 'molecular' sleep and cancer. My research focus has largely been on understanding the hypoxic (low oxygen) response in solid tumours and developing anti-cancer drugs that target this pathway. 

Tumour cells grow very fast and they grow faster than new blood vessels. The tumour runs out of oxygen and becomes hypoxic, which increases chemotherapy resistance and makes the tumour harder to treat. I have been developing drugs to inhibit this pathway for many years.

I became interested in sleep through my hypoxia research and the finding that cancer patients with sleep apnoea have worse outcomes.  Sleep apnoea causes hypoxia and my hypothesis is that the hypoxia and the 'hypoxia inducible factor' (HIF) may be leading to worse outcomes.

Another area of cancer and sleep we are working in is circadian rhythms, which are our 24hr internal clocks that drive things like sleep and eating. These rhythms are encoded as a 'molecular clock' in our genes and disrupted rhythms have been linked to cancer, particularly brain cancer. I'm looking how cellular circadian rhythms alter growth and invasion of glioblastoma, a particularly aggressive and hard to treat form of brain cancer. We hope to identify new treatment options for brain cancer.

Sleep is largely associated with the behavioral, physiological and psychological research fields but there are numerous molecular changes that occur in the area of sleep. My work identifies the molecular and cellular changes in tumour cells that occur within the context of 'sleep' and in particular sleep disorders. Ultimately, I hope our research will lead to new cancer treatments.

Humans spend about one-third of their lives sleeping and sleep disturbances are associated with numerous adverse health outcomes including cardiovascular disease.
Dr Hasthi Dissanayake
Dr Hasthi Dissanayake

Dr Hasthi Dissanayake, postdoctoral researcher and Colin Sullivan Fellow, Northern Clinical School 

Dr Hasthi Dissanayake

My background is in cardiovascular physiology and non-invasive techniques for assessing vascular health. I completed my PhD at the University of Sydney investigating early origins of cardiovascular disease. Following on I was appointed the Colin Sullivan Fellowship in Sleep Research, at the University of Sydney. This fellowship is dedicated to investigating the links between sleep-disordered breathing and chronic diseases.

My current focus is conducting an obstructive sleep apnea (OSA) prevalence study in patients with a recent heart attack, with an overarching goal in assessing OSA treatment compliance and effect on surrogate markers of vascular health. 

Humans spend about one-third of their lives sleeping and sleep disturbances are associated with numerous adverse health outcomes including cardiovascular disease. Obstructive sleep apnoea (OSA) is a serious sleep disorder which causes breathing to repeatedly stop and start during sleep. The perturbation caused by OSA have a major impact on the cardiovascular system and is an independent risk factor for coronary artery disease, affecting 40%-50% of cardiac patients. Our own studies in patients with a recent heart attack show a staggering 92% have OSA.

Despite current best treatment and traditional risk factor modification by diet, exercise and anti-smoking interventions, cardiovascular disease remains the leading cause of death and disability in Australia. The shared pathophysiology between conditions and the high prevalence of both diseases indicate a role for OSA in the prevention of cardiovascular disease. Therapies that counteract these disease pathways may slow down disease progression and improve cardiac function and survival. Therefore, treating OSA in isolation maybe key for cardiovascular risk reduction.

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